// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_APPCACHE_APPCACHE_STORAGE_IMPL_H_
#define CONTENT_BROWSER_APPCACHE_APPCACHE_STORAGE_IMPL_H_

#include <stdint.h>

#include <deque>
#include <map>
#include <set>
#include <utility>
#include <vector>

#include "base/callback.h"
#include "base/files/file_path.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/timer/timer.h"
#include "content/browser/appcache/appcache_database.h"
#include "content/browser/appcache/appcache_disk_cache.h"
#include "content/browser/appcache/appcache_storage.h"
#include "content/common/content_export.h"

namespace base {
class SingleThreadTaskRunner;
} // namespace base

namespace content {
class AppCacheStorageImplTest;
class ChromeAppCacheServiceTest;

class AppCacheStorageImpl : public AppCacheStorage {
public:
    explicit AppCacheStorageImpl(AppCacheServiceImpl* service);
    ~AppCacheStorageImpl() override;

    void Initialize(
        const base::FilePath& cache_directory,
        const scoped_refptr<base::SingleThreadTaskRunner>& db_thread,
        const scoped_refptr<base::SingleThreadTaskRunner>& cache_thread);
    void Disable();
    bool is_disabled() const { return is_disabled_; }

    // AppCacheStorage methods, see the base class for doc comments.
    void GetAllInfo(Delegate* delegate) override;
    void LoadCache(int64_t id, Delegate* delegate) override;
    void LoadOrCreateGroup(const GURL& manifest_url, Delegate* delegate) override;
    void StoreGroupAndNewestCache(AppCacheGroup* group,
        AppCache* newest_cache,
        Delegate* delegate) override;
    void FindResponseForMainRequest(const GURL& url,
        const GURL& preferred_manifest_url,
        Delegate* delegate) override;
    void FindResponseForSubRequest(AppCache* cache,
        const GURL& url,
        AppCacheEntry* found_entry,
        AppCacheEntry* found_fallback_entry,
        bool* found_network_namespace) override;
    void MarkEntryAsForeign(const GURL& entry_url, int64_t cache_id) override;
    void MakeGroupObsolete(AppCacheGroup* group,
        Delegate* delegate,
        int response_code) override;
    void StoreEvictionTimes(AppCacheGroup* group) override;
    AppCacheResponseReader* CreateResponseReader(const GURL& manifest_url,
        int64_t response_id) override;
    AppCacheResponseWriter* CreateResponseWriter(
        const GURL& manifest_url) override;
    AppCacheResponseMetadataWriter* CreateResponseMetadataWriter(
        int64_t response_id) override;
    void DoomResponses(const GURL& manifest_url,
        const std::vector<int64_t>& response_ids) override;
    void DeleteResponses(const GURL& manifest_url,
        const std::vector<int64_t>& response_ids) override;

private:
    // The AppCacheStorageImpl class methods and datamembers may only be
    // accessed on the IO thread. This class manufactures seperate DatabaseTasks
    // which access the DB on a seperate background thread.
    class DatabaseTask;
    class InitTask;
    class DisableDatabaseTask;
    class GetAllInfoTask;
    class StoreOrLoadTask;
    class CacheLoadTask;
    class GroupLoadTask;
    class StoreGroupAndCacheTask;
    class FindMainResponseTask;
    class MarkEntryAsForeignTask;
    class MakeGroupObsoleteTask;
    class GetDeletableResponseIdsTask;
    class InsertDeletableResponseIdsTask;
    class DeleteDeletableResponseIdsTask;
    class LazyUpdateLastAccessTimeTask;
    class CommitLastAccessTimesTask;
    class UpdateEvictionTimesTask;

    typedef std::deque<DatabaseTask*> DatabaseTaskQueue;
    typedef std::map<int64_t, CacheLoadTask*> PendingCacheLoads;
    typedef std::map<GURL, GroupLoadTask*> PendingGroupLoads;
    typedef std::deque<std::pair<GURL, int64_t>> PendingForeignMarkings;
    typedef std::set<StoreGroupAndCacheTask*> PendingQuotaQueries;

    bool IsInitTaskComplete()
    {
        return last_cache_id_ != AppCacheStorage::kUnitializedId;
    }

    CacheLoadTask* GetPendingCacheLoadTask(int64_t cache_id);
    GroupLoadTask* GetPendingGroupLoadTask(const GURL& manifest_url);
    void GetPendingForeignMarkingsForCache(int64_t cache_id,
        std::vector<GURL>* urls);

    void ScheduleSimpleTask(const base::Closure& task);
    void RunOnePendingSimpleTask();

    void DelayedStartDeletingUnusedResponses();
    void StartDeletingResponses(const std::vector<int64_t>& response_ids);
    void ScheduleDeleteOneResponse();
    void DeleteOneResponse();
    void OnDeletedOneResponse(int rv);
    void OnDiskCacheInitialized(int rv);
    void DeleteAndStartOver();
    void DeleteAndStartOverPart2();
    void CallScheduleReinitialize();
    void LazilyCommitLastAccessTimes();
    void OnLazyCommitTimer();

    // Sometimes we can respond without having to query the database.
    bool FindResponseForMainRequestInGroup(
        AppCacheGroup* group, const GURL& url, Delegate* delegate);
    void DeliverShortCircuitedFindMainResponse(
        const GURL& url,
        const AppCacheEntry& found_entry,
        scoped_refptr<AppCacheGroup> group,
        scoped_refptr<AppCache> newest_cache,
        scoped_refptr<DelegateReference> delegate_ref);

    void CallOnMainResponseFound(DelegateReferenceVector* delegates,
        const GURL& url,
        const AppCacheEntry& entry,
        const GURL& namespace_entry_url,
        const AppCacheEntry& fallback_entry,
        int64_t cache_id,
        int64_t group_id,
        const GURL& manifest_url);

    // Don't call this when |is_disabled_| is true.
    CONTENT_EXPORT AppCacheDiskCache* disk_cache();

    // The directory in which we place files in the file system.
    base::FilePath cache_directory_;
    bool is_incognito_;

    // This class operates primarily on the IO thread, but schedules
    // its DatabaseTasks on the db thread. Separately, the disk_cache uses
    // the cache thread.
    scoped_refptr<base::SingleThreadTaskRunner> db_thread_;
    scoped_refptr<base::SingleThreadTaskRunner> cache_thread_;

    // Structures to keep track of DatabaseTasks that are in-flight.
    DatabaseTaskQueue scheduled_database_tasks_;
    PendingCacheLoads pending_cache_loads_;
    PendingGroupLoads pending_group_loads_;
    PendingForeignMarkings pending_foreign_markings_;
    PendingQuotaQueries pending_quota_queries_;

    // Structures to keep track of lazy response deletion.
    std::deque<int64_t> deletable_response_ids_;
    std::vector<int64_t> deleted_response_ids_;
    bool is_response_deletion_scheduled_;
    bool did_start_deleting_responses_;
    int64_t last_deletable_response_rowid_;

    // Created on the IO thread, but only used on the DB thread.
    AppCacheDatabase* database_;

    // Set if we discover a fatal error like a corrupt SQL database or
    // disk cache and cannot continue.
    bool is_disabled_;

    std::unique_ptr<AppCacheDiskCache> disk_cache_;
    base::OneShotTimer lazy_commit_timer_;

    // Used to short-circuit certain operations without having to schedule
    // any tasks on the background database thread.
    std::deque<base::Closure> pending_simple_tasks_;
    base::WeakPtrFactory<AppCacheStorageImpl> weak_factory_;

    friend class content::AppCacheStorageImplTest;
    friend class content::ChromeAppCacheServiceTest;
};

} // namespace content

#endif // CONTENT_BROWSER_APPCACHE_APPCACHE_STORAGE_IMPL_H_
